Channel characterization for unmanned aircraft systems

Unmanned aircraft systems (UAS), also known as unmanned aerial vehicles, or by the misnomer “drones,” are seeing explosive growth, and this growth is expected to continue for the foreseeable future. Hence numerous entities are involved with research, design, and testing to ensure safe and reliable UAS operation in the worldwide airspace. Since many UAS will be small and highly maneuverable, air-ground channel conditions will differ from - and often be more challenging than - those of traditional piloted aircraft, where ground sites are in open areas with tall antenna towers. Thus new research is required to accurately characterize the air-ground channel. We provide motivation for accurate air-ground channel characterization and modeling, and briefly define the main characteristics of the air-ground channel. Various channel modeling options are described. We provide example air-ground channel measurement results from our work with NASA, discuss initial air-ground channel models, and future work.